Metadata for a term in a document. More...

#include <terminfo.h>

Collaboration diagram for TermInfo:

Public Member Functions
	TermInfo (Xapian::termcount wdf_)
	Constructor. More...

	TermInfo (Xapian::termcount wdf_, Xapian::termpos termpos)
	Constructor which also adds an initial position. More...

const Xapian::VecCOW< Xapian::termpos > *	get_positions () const
	Get a pointer to the positions. More...

bool	has_positions () const

size_t	count_positions () const

Xapian::termcount	get_wdf () const
	Get the within-document frequency. More...

bool	increase_wdf (Xapian::termcount delta)
	Increase within-document frequency. More...

bool	decrease_wdf (Xapian::termcount delta)
	Decrease within-document frequency. More...

bool	remove ()

bool	add_position (Xapian::termcount wdf_inc, Xapian::termpos termpos)
	Add a position. More...

void	append_position (Xapian::termpos termpos)
	Append a position. More...

bool	remove_position (Xapian::termpos termpos)
	Remove a position. More...

Xapian::termpos	remove_positions (Xapian::termpos termpos_first, Xapian::termpos termpos_last)
	Remove a range of positions. More...

bool	is_deleted () const
	Has this term been deleted from this document? More...

Private Member Functions
void	merge () const
	Merge sorted ranges before and after split. More...

Private Attributes
Xapian::termcount	wdf

unsigned	split = 0
	Split point in the position range. More...

Xapian::VecCOW< Xapian::termpos >	positions
	Positions at which the term occurs. More...

Detailed Description

Metadata for a term in a document.

Definition at line 28 of file terminfo.h.

Constructor & Destructor Documentation

◆ TermInfo() [1/2]

TermInfo::TermInfo ( Xapian::termcount wdf_ )

inlineexplicit

Constructor.

Parameters

wdf_	Within-document frequency

Definition at line 65 of file terminfo.h.

◆ TermInfo() [2/2]

TermInfo::TermInfo	(	Xapian::termcount	wdf_,
		Xapian::termpos	termpos
	)

inline

Constructor which also adds an initial position.

Parameters

wdf_	Within-document frequency
termpos	Position to add

Definition at line 72 of file terminfo.h.

References positions.

Member Function Documentation

◆ add_position()

bool TermInfo::add_position	(	Xapian::termcount	wdf_inc,
		Xapian::termpos	termpos
	)

Add a position.

If termpos is already present, this is a no-op.

Parameters

wdf_inc	wdf increment
termpos	Position to add

Returns: true if the term was flagged as deleted before the operation.

Definition at line 43 of file terminfo.cc.

References AssertRel, and rare.

◆ append_position()

void TermInfo::append_position ( Xapian::termpos termpos )

inline

Append a position.

The position must be >= the largest currently in the list.

Definition at line 145 of file terminfo.h.

References positions.

◆ count_positions()

size_t TermInfo::count_positions ( ) const

inline

Definition at line 84 of file terminfo.h.

References positions.

◆ decrease_wdf()

bool TermInfo::decrease_wdf ( Xapian::termcount delta )

inline

Decrease within-document frequency.

Returns: true If the adjusted wdf is zero and there are no positions.

Definition at line 107 of file terminfo.h.

References positions, split, and wdf.

◆ get_positions()

const Xapian::VecCOW<Xapian::termpos>* TermInfo::get_positions ( ) const

inline

Get a pointer to the positions.

Definition at line 77 of file terminfo.h.

References merge(), positions, and split.

◆ get_wdf()

Xapian::termcount TermInfo::get_wdf ( ) const

inline

Get the within-document frequency.

Definition at line 87 of file terminfo.h.

References wdf.

◆ has_positions()

bool TermInfo::has_positions ( ) const

inline

Definition at line 82 of file terminfo.h.

References positions.

◆ increase_wdf()

bool TermInfo::increase_wdf ( Xapian::termcount delta )

inline

Increase within-document frequency.

Returns: true if the term was flagged as deleted before the operation.

Definition at line 93 of file terminfo.h.

References is_deleted(), rare, split, and wdf.

◆ is_deleted()

bool TermInfo::is_deleted ( ) const

inline

Has this term been deleted from this document?

We flag entries as deleted instead of actually deleting them to avoid invalidating existing TermIterator objects.

Definition at line 174 of file terminfo.h.

References positions, and split.

Referenced by increase_wdf(), and remove().

◆ merge()

void TermInfo::merge ( ) const

private

Merge sorted ranges before and after split.

Definition at line 33 of file terminfo.cc.

References Assert.

Referenced by get_positions().

◆ remove()

bool TermInfo::remove ( )

inline

Definition at line 122 of file terminfo.h.

References is_deleted(), positions, and split.

◆ remove_position()

bool TermInfo::remove_position ( Xapian::termpos termpos )

Remove a position.

Parameters

termpos Position to remove

Returns: If termpos wasn't present, returns false.

Definition at line 110 of file terminfo.cc.

References Assert, and rare.

◆ remove_positions()

Xapian::termpos TermInfo::remove_positions	(	Xapian::termpos	termpos_first,
		Xapian::termpos	termpos_last
	)

Remove a range of positions.

Parameters

termpos_first	First position to remove
termpos_last	Last position to remove

It's OK if there are no positions in the specified range.

Returns: the number of positions removed.

Definition at line 145 of file terminfo.cc.

References Assert.

Member Data Documentation

◆ positions

Xapian::VecCOW<Xapian::termpos> TermInfo::positions

mutableprivate

Positions at which the term occurs.

The entries are sorted in strictly increasing order (so duplicate entries are not allowed).

Definition at line 55 of file terminfo.h.

Referenced by append_position(), count_positions(), decrease_wdf(), get_positions(), has_positions(), is_deleted(), remove(), and TermInfo().

◆ split

unsigned TermInfo::split = 0

mutableprivate

Split point in the position range.

To allow more efficient insertion of positions, we support the positions being split into two sorted ranges, and if this is the case, split will be > 0 and there will be two sorted ranges [0, split) and [split, positions.size()).

If split is 0, then [0, positions.size()) form a single sorted range.

If positions.empty(), then split > 0 indicates that the term has been deleted (this allows us to delete terms without invalidating existing TermIterator objects).

Use type unsigned here to avoid bloating this structure. More than 4 billion positions in one document is not sensible (and not possible unless termpos is configured to be 64 bit).

Definition at line 48 of file terminfo.h.

Referenced by decrease_wdf(), get_positions(), increase_wdf(), is_deleted(), and remove().

◆ wdf

Xapian::termcount TermInfo::wdf

private

Definition at line 29 of file terminfo.h.

Referenced by decrease_wdf(), get_wdf(), and increase_wdf().

The documentation for this class was generated from the following files:

api/terminfo.h
api/terminfo.cc

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ TermInfo() [1/2]

◆ TermInfo() [2/2]

Member Function Documentation

◆ add_position()

◆ append_position()

◆ count_positions()

◆ decrease_wdf()

◆ get_positions()

◆ get_wdf()

◆ has_positions()

◆ increase_wdf()

◆ is_deleted()

◆ merge()

◆ remove()

◆ remove_position()

◆ remove_positions()

Member Data Documentation

◆ positions

◆ split

◆ wdf